UV disinfection alternative to inactivate microorganisms - atg

By Joseph James Whitworth

- Last updated on GMT

atg UV system
atg UV system

Related tags Dna Bacteria

The success of UV disinfection depends on the applied dose being sufficient to inactivate the target microorganisms, according to atg UV Technology.

The UK manufacturer of ultraviolet water disinfection systems for the food and beverage industry said UV systems can be used for process applications, from CIP rinsing to liquid sugar.

Waterborne microorganisms are responsible for adverse effects on flavour, colour, odour and shelf life of products and potential health risks to consumers.

Not selective as a technique

Duncan Ockendon, sales manager at atg UV Technology, said common applications include product or process water and sugar/syrup.

“We have a range of systems…the three parameters are flow rate of water, second is UV transmittance of water and third is understanding the nature of challenging organisms,” ​he told FoodQualityNews.

“What microorganism is of concern to the customer as different microorganisms have different responses to UV light? Knowing the organism helps select the UV dose used to inactivate it, if the customer doesn’t know then we use a sufficient UV dose to inactivate all known organisms.

“It is a learning curve [when speaking to potential customers], there are misleading descriptions on how it works, it is not heat created by the lamps that kills the pathogens, they think it is associated with ionizing radiation, and a general misunderstanding of how it works.

“UV acts on the DNA in the nucleus of an organism and changes the state so the organism can’t replicate. All life is based on RNA or DNA no possible organism could develop resistance to UV.”

Resistance and alternatives

UV irradiation has a history in pharmaceutical and drinking water disinfection where 254nm UVC light, at the correct and consistent dosage, inactivates waterborne microorganisms, including bacteria, moulds, yeasts and algae.

Pathogens such as Cryptosporidium and Giardia are showing increased resistance to chlorine disinfection, but are treatable with UV light, said Ockendon.

“Chlorine remains a staple chemical disinfectant product in food and beverage, the issue is with taste and odour. UV light doesn’t introduce any chemical substances into the water,” ​he said.

“Ozone is sometimes used but it is toxic, so needs to be handled with care and it is highly oxidising, so could damage product ingredients, flavour or taste.

“UV dose is a factor of UV intensity power and the number of lamps in the chamber. You could have a low power lamp and long contact time or powerful lamps and short contact time, typically of one second.”

Ockendon added one retailer, within the last year, requires UV systems are used due to the growing awareness of resistance to chlorine. 

Atg’s systems match the US EPA guidelines for equipment validation – a standard adopted for UV disinfection systems.

The best place to put a system is as close to the point of water use as possible, said Ockendon.

“The UV transmittance parameter is affected by dissolved and suspended solids, if light doesn’t pass through it is not treated,” ​he said.

“It is for water about to be used but not including the product, you can’t use for milk and juice, but you can use for water in a product or for water used to clean the plant.

“It can be installed in several locations, to treat incoming water used for different purposes and a second treatment before water goes into use such as water about to be mixed, at that point another UV system could be used in case of accidental contamination.”

Ockendon added soft drink bottlers require third party validation as a guarantee of performance and it has done such validation for a number of models and will continue to do so as budget allows.

Third party validations are applied on the model built by a manufacturer and cost around £50,000.

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